Introduction to optical characterization of materials

Abstract

Have you ever seen the colors dancing on the surface of a soap bubble? Or the red glow of a hot object? Have admired the iridescent colors on the wings of a butterfly? Or noticed the different colors of “Neon” signs? These are a few examples of how the physical, chemical, and structural properties of an object, as thickness, temperature, microstructure, or chemical composition on the examples above, affect the way that object interacts with photons. This effect can be used to determine those properties. Using photons of light to determine materials properties is what we call optical characterization. In this chapter we give a brief introduction to a few of the most popular examples of these techniques, with an emphasis on its applicability, usefulness, and limitations. We will talk about techniques that can be used complementarily and discuss some of the hurdles which are commonly encountered when using them in practical, real world application examples, offering suggestions on how to avoid them whenever possible. Specific techniques covered in the chapter are Raman scattering spectroscopy, ellipsometry, spectrophotometry (UV-VIS), and Fourier transform infra-red spectroscopy (FTIR).